Hibiscus plant named &#39;DUP-SWPK&#39;

ABSTRACT

A new and distinct cultivar of  Hibiscus  plant named ‘DUP-SWPK’, characterized by glossy, dark green leaves, semi-upright habit appropriate for container production and culture, freely flowering habit, and very large pendant double flowers which are uniformly cream pink throughout.

LATIN NAME OF THE GENUS AND SPECIES

Hibiscus rosa-sinensis

VARIETY DENOMINATION

‘DUP-SWPK’

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ifHibiscus, botanically known as Hibiscus rosa-sinensis and hereinafterreferred to by the cultivar name ‘DUP-SWPK.’

Hibiscus have been the subject of human admiration for centuries. Whilethe ancestry of present rosa-sinensis hybrids is not be precisely known,todays hybrids are thought to be the products of interspecific crossesinvolving Hawaiian, Polynesian and Asian species, among others, some ofwhich may no longer be found in the wild, if at all. It is thought thatthe first hibiscus identified as a “rosa-sinensis” was a double red formof uncertain origin found in cultivation in China, India and Polynesia,to be later introduced to Hawaii from Polynesia. It is known to havebeen grown in Europe during the Victorian era. Eventually, it wasintroduced to the continental United States where it was cultivatedoutdoors in the Deep South as well as in regions having subtropical orMediterranean climates (Florida and Southern California, respectively).Indoor cultivation took place in the temperate regions of the U.S. It isspeculated that the original “rosa-sinensis” is actually a specieshybrid, possibly naturally arising, involving two or more species.Regardless, present day hybrids are descended from the original doubleform, and are thought to include additional species such as Hibiscusliliiflorus, H. arnottianus, H. schizopetalus, and other species, knownand unknown, some of which are no longer found in the wild, if at all.Today, after decades of extensive hybridization, the moniker“rosa-sinensis” almost certainly denotes complex interspecific hybrids.Such hybrids are usually far removed from their species ancestors inform and color. Flowers of spectacular size, color intensity and, in thelast several decades, ringed and spotted patterns have been produced byU.S. hybridizers primarily in Louisiana, Florida, Texas and elsewhere.Other hotbeds of activity include Australia, and more recently, Tahiti.Today's flowers are removed from their species ancestors to such anextent that it is almost impossible to unravel the species componentcontributions which comprise a modern hybrid hibiscus.

However, despite the fact that extensive hybridization was giving riseto larger blossoms and more intense colors, few early hybrids attractedthe attention of large scale propagators. While the flowers were some ofthe most impressive in the entire plant world, hybridizer selection forbloom characteristics alone resulted in weak, short-lived plants. Manyvarieties were difficult to root from cuttings and some only grewacceptably as grafted plants. Grafted plants suffered from a seriousdisadvantage in that the quality of the graft generally determined thequality of the plant, making the production of uniformly vigorous plantsa difficult task. Furthermore, after several years, it was common forgrafted plants to develop stresses at the graft union due to the unequalgrowth rates of the rootstock and the scion. Such stresses caneventually lead to loss of vigor and death of the plant. Moreover,grafting did not completely cure the problem of root rot—surprisingly,the rootstock, when grafted to a root-rot susceptible scion was oftenmore likely to suffer rot than the a plant of the rootstock variety. Forexample, a plant of “Seminole Pink,” a garden variety commonly used as arootstock, is highly resistant to root rot. However, when Seminole Pinkis used as a rootstock for “Romeo,” a modern hybrid which is prone toroot rot, the grafted plant, while less susceptible than Romeo, is moresusceptible than a plant of Seminole Pink. Another disadvantage ofgrafted plants is the introduction of viruses into the scion from therootstock. Rootstock varieties are almost invariably old gardenvarieties which, over the years, have become infected with multipleviruses. While the performance of such vigorous garden varieties may belargely unaffected by the virus infection, the hybrid scion of graftedplants were usually significantly less vigorous than the garden varietyrootstock, and virus infection from the rootstock resulted in a weakplant. The problem only increased with successive generations ofgrafting, resulting in a general weakening of a given variety over time.

As a result, the flower production of many modern hybrids was generallysparse with a high number of deformed blooms. Furthermore, buds oftentook relatively long times to reach blooming stage, and it was notuncommon to wait with anticipation while a bud swelled day by day, onlyto be disappointed when the mature bud toppled from its pedicel on theday it was to open. Moreover because of hybridizer emphasis on theflower, the plant was often relatively slow growing and sparsely clothedin leaves.

Such characteristics left hibiscus with the reputation that, despite themesmerizing beauty of the flowers, they were for collectors who had timeto attend to the seemingly exacting requirements of the plants. As aresult, while new varieties were produced by hobbyists yearly,commercial scale propagation of modern hybrids was generally rare.Common garden varieties (Seminole Pink, Brilliant, President, PaintedLady, Butterfly, Lagos and others), which are easy to root, fastgrowing, and tolerant of a wide range of growing conditions were theonly hibiscus widely available.

Many new varieties of hibiscus which represent a vast improvement inrosa-sinensis hybrids, have been produced by an intense hybridizingprogram conducted by the Inventor at his commercial nursery inPlaquemine, La. The objective of the program has been to producevarieties of hibiscus which root easily under commercial rootingconditions, grow well on their own roots, maturing rapidly intowell-leaved, commercially salable plants under commercial greenhouseconditions. Further objectives are to produce Hibiscus cultivars asaforementioned, having large-flowers with unique and desirable flowercharacteristics, such as size, color intensity and pattern.

Asexual reproduction of the new Hibiscus by hard wood, semi hardwood,and terminal cuttings taken in a controlled environment in Plaquemine,La., has shown that the unique features of this new Hibiscus are stableand reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

The cultivar ‘DUP-SWPK’ has not been observed under all possibleenvironmental variables. The phenotype may vary somewhat with variationsin environment such as temperature, light intensity, nutrition and waterstatus without, however, any variation in genotype. For example, duringcooler weather, flowers may demonstrate an increased intensity in pinktones, Furthermore, as with many varieties of Hibiscus, cooler weathercan result in a decrease in flower diameter, and a correspondingreduction in size of sepals and pistil. Moreover, as indicated below,plant characteristics vary greatly with culture, with internode spacingsoften increasing in warmer weather and with higher fixed nitrogen soilcontent. Plants grown at higher temperatures also exhibit a faster rateof growth. In general the plant used in the following description wasgrown at temperatures which never dipped below 55 F. Because theInventor's one gallon plants are grown for an average time of about 5.5to 6 months prior to sale, and the 10 inch pot plants are grown for aaverage time of about 7 to 8 months prior to sale, it is difficult toprovide a precise temperature profile required to give the average plantmeasurements described in the below description. The growing period canencompass several seasons, with seasonal fluctuations in high/lowtemperatures as well as photo period. It is expected that the daily hightemperature ranged from about 70 F to about 95 F, and the daily lowtemperature, which never dipped below 55 F, ranged from about 65 F toabout 80 F.

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘DUP-SWPK.’ These characteristics incombination distinguish ‘DUP-SWPK’ as a new and distinct cultivar.

-   1. Glossy, dark green leaves.-   2. Semi-upright habit appropriate for container production and    culture.-   3. Freely flowering habit.-   4. Very large pendant double flowers which are uniformly cream pink    throughout.-   5. The plant is at least as free-flowering as each parent, and has    been found to root more easily under greenhouse conditions than    either parent.

BRIEF DESCRIPTION OF THE PHOTOGRAPH(S)

The accompanying colored photographs illustrate the overall appearanceof the new Hibiscus, showing the colors as true as it is reasonablypossible to obtain in colored reproductions of this type.

Colors in the photographs may differ slightly from the color valuescited in the detailed botanical description which accurately describethe colors of the new Hibiscus.

The photograph on the first sheet comprises a bloom.

The photograph on the second sheet comprises a double plant of‘DUP-SWPK’ in a standard nursery gallon pot.

The photograph on the third sheet is of two representative mature leavesof ‘DUP-SWPK.’

The photograph on the fourth sheet comprises a profile of a second dayflower demonstrating the proportions of the pistil compared to the bloomdiameter. The calyx is clearly visible.

The photo on the fifth sheet comprises the bloom reverse.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The RoyalHorticultural Society Colour Chart except where general terms ofordinary dictionary significance are used. The following observations,measurements, and values describe plants grown in Plaquemine, La., withtwo plants per 1 gallon container. Plants used for the description wereabout 24 weeks old.

-   Botanical classification: Hibiscus rosa-sinensis.-   Parentage:    -   -   Female or seed parent.—Gator Pride (not patented).        -   Male or pollen parent.—Blue Thunder (not patented).-   Propagation:    -   -   Type.—cuttings DUP-SWPK has been propagated by taking            hardwood, semi hardwood, and tip cuttings, with semi            hardwood preferred. It should be noted that many methods of            assexual propagation, such as tissue culture and other            cloning processes, can be expected to show some degree of            success in the propagation of the present cultivar, although            . However, of the methods tried by the inventor, the use of            semi hardwood cutting has given the greatest yield of            commercially salable plants. Asexual propagation has            resulted in plants which have the flower and plant            characteristics of the original DUP-SWPK plant, and thus the            variety is stable. Cuttings from DUP-SWPK generally root            well under commercial greenhouse conditions. While            greenhouse conditions such as relative humidity and other            factors such as cutting age prior to planting affect the            take, it is not unusual to get a take of almost 100%. Please            note that as successive generations of cuttings are raised,            the raiser may experience a drop in take due to the            incorporation of virus, particularly if at some point            grafted plants are prepared, and cuttings are taken from            such a plant.        -   Time to initiate roots.—An average time of initiation at            approximately 22 C is approximately six weeks, with slightly            longer times during winter at comparable temperatures, and            slightly shorter during summer at comparable temperatures.        -   Time to develop roots.—An average time, at approximately 22            C, of development of a root system after initiation, is            approximately six weeks, with slightly longer times during            winter at comparable temperatures, and slightly shorter            during summer at comparable temperatures. It should be noted            that root initiation and development can be affected by            greenhouse conditions, biological stressors such as disease            organisms, as well as environmental stressors such as low or            variant relative humidity, over- and under-watering,            temperature variations or high or low constant temperatures.            Furthermore, Thus, rooting times can be shorter or longer            than the times given above depending on the values of many            different characteristics during the rooting process known            in the art.        -   Root description.—Fibrous and well-branched.-   Plant description:    -   -   Plant form and growth habits.—Perennial evergreen having            upright, rangy, lanky, tall growth. Not generally a compact,            sturdy grower, but internodal space can be dependent upon            greenhouse temperature time profile, fertilizer time            profile, and other factors.        -   Branching habit.—only moderately well-branched, having            approximately 1-2 laterals when a single stem plant is            pinched back to a 5 inch height.        -   Plant height, soil level to top of flowers.—a salable plant            (having 2 separate plants) in a 1 gallon nursery pot can be            approximately 24 inches high and 24 inches wide. Please note            that cultural variables such as greenhouse temperature time            profile, fertilizer level, and other factors can cause            significant variation from the values given herein.        -   Lateral branch description.—The average branch            characteristics of a salable 1 gallon plant: Average Length:            approximately 15″. Average Diameter: approximately 0.8 cm            measured at the transition from green to woody stem texture.            Texture: Immature, smooth; mature, woody and rough. Color:            Immature: Green, more green than 147A. Mature: Brownish            gray, close to 200C with 197A overtones.-   Mature Foliage description:    -   -   Arrangement.—Alternate, single; numerous; symmetrical.        -   Length.—approximately 12.4 cm.        -   Width.—approximately 10.1 cm.        -   Shape.—ovate.        -   Apex.—acute.        -   Margin.—crenate.        -   Texture.—glabrous, rugose.        -   Color.—Young foliage, upper surface: More green than 147A;            very glossy. Mature foliage, upper surface: Generally darker            than 147A; glossy.        -   Petiole.—Average Length: 3.1 cm Average Diameter: 0.3 cm            Texture: Fine pubescence on upper surface; lower surface,            glabrous. Color: Dark greenish brown; close to 200A with            undertones of 147A. It should be noted that as with other            plant growth characteristics foliage color and size can vary            somewhat with fertilization regimen, greenhouse temperature,            daylength, and other conditions of culture.-   Flower description:    -   -   Natural flowering season.—year round, with number and size            reduction in extended periods of cold weather, such as            daytime temperatures of less than 60 C. Extreme heat can            slow growth and flower production.        -   Flower arrangement.—Flowers arranged singly at terminal leaf            axils. Very free-flowering, with usually about two or three            developing flower buds per lateral branch, flowers are            mostly pendant.        -   Flower appearance.—Large, rounded single flowers. Flowers            are open for one to two days before senescence, which is            often accompanied by partial or full petal closure. Flowers            persistent.        -   Flower diameter.—DUP-SWPK flowers are generally in the range            of from about 8-9″ when fully open, with largest flowers            produced during warm weather (for example, day and night            time temperatures above 73 degrees F.        -   Flower depth.—Flower depth was measured to average            approximately 2 cm. Flower depth was measured after removal            of a petal and a sepal to expose the base of the pistil. The            measurement was taken on a fully opened flower in the            direction of the pistil, from the base of the ovaries to the            maximum height of the flower petal, which is the point of            recurvature of the petal. It should be noted that hibiscus            blossoms can flatten out during the day, or increase or            decrease in curvature or degree of petal reflex during the            day, and thus variance from the foregoing value is possible.        -   Flower bud (just before showing color).—Rate of opening: 1-3            days. Rate of opening is generally faster in warmer weather.            Flower bud dimensions were measured on a bud which was            approximately two days from opening. The measurements were            as follows. Bud length was measured from the abscission zone            where bud and peduncle meet to the tip of the bud. The            average length of a bud which is one day from opening is            approximately 9.8 cm. Bud diameter was measured at the            widest part of the bud, an area approximately halfway up the            outside of the developing petals. The average diameter of a            bud which is one day from opening is approximately 2.9 cm.            It should be noted that bud dimensions can vary somewhat            with cultural conditions, and variations can even be            observed in buds which are at the same stage of development.            Shape: elliptic Color: More green than 147A.        -   Petals.—Texture: Smooth, satiny, rugose. Arrangement: The            corolla consists of five petals arranged in a whorl, having            regular partial overlap, even when the flower is fully open.            Flowers comprise a doubling ruff of petal tissue, largely or            entirely originating from staminal column tissue.        -   Shape.—roughly spatulate, with a rounded apex and a truncate            base. The margin of each petal undulate and entire. Petals            can be strongly recurved, with little overlap when flower is            entirely open. A representative length was measured to be            8.5 cm, and was taken from the base of the petal to the            farthest point on the margin opposite the base. A            representative width is 8.4 cm, and was measured            perpendicularly to the pistil at the widest point of the            petal. Petal size can vary with cultural conditions, such as            temperature, and thus the flower size and shape can vary as            well. Often, flowers which are produced at colder            temperatures are smaller and appear more fully overlapped.            When fully open, the edges of DUP-SWPK flowers often recurve            stiffly. The color of a warm weather flower is described            below. It has been observed that colder temperatures can            result in the stronger expression of pink tones in the            petals. It should be noted that the colors of hibiscus are            among the most changeable of all flowers. A newly opening            morning bloom generally has the most intense coloration, but            as the flower flattens out and is exposed to the sun, many            pigments begin to fade immediately, resulting in a flower            which can look like a different variety altogether. Unlike            many hibiscus varieties of stronger coloration, the flowers            of DUP-SWPK fade relatively little by the second day, with            the flower generally only taking on a translucent cast. The            morning colors are described below. Color: Upper surface:            Margin: 56D Center: 56D Base: 56D Lower surface: Left side:            11C Right side: 11D.        -   Sepals.—Unlike the petals, sepals are relatively invariant            in color. Their size can be affected by same cultural            conditions which affect flower size, They are generally            smooth and elongated oblong with acute apices (pointed            tips). They are fused at the long edges into a cupped calyx            bearing at its brim the five pointed tips. When the petals            of the flower spread open, the five pointed tips, which are            flush with the backs of the opening petals, are forced into            a radiating five point star-shaped configuration, which can            be observed on the profile and reverse pictures. A            representative width, which is measured perpendicularly to            the long axis of the sepal a at the position on the sepal at            which the oblong edges transition from fused to unfused, is            approximately 1.3 cm. A representative length, measured on            the sepal from the free point to the fused point is            approximately 3.1 cm. Color: Upper surface: Close to 146A.            Lower surface: Close to 147A.        -   Peduncle.—Length: 5.8 cm Angle: approximately 35 degrees            from branch Strength: Strong, flexible Texture: smooth            Color: Slightly darker than 146A.        -   Reproductive organs.—Androecium: Stamen number:            approximately 75 Anther shape: crescent Anther color: 11D            Amount of pollen: moderate Pollen color: 23B Gynoecium:            Pistil number: 1 Pistil length (from base of ovaries to top            of stigma): 7 cm Style length (from base of ovaries to            stigma branching point): 6.2 cm Style diameter, at base: 1            cm Style color: Base: 11C Midsection: 12C Apex: 11D Stimga            number: often 5, but can vary Stigma color: 45C It should be            noted that the dimensions of a hibiscus blossom generally            change not only during bud development, but also during            opening, as well as during the life of the opened flower.            For instance, upon opening, the petals generally gain in            length. Double varieties gain significant mass during            opening. Furthermore, after opening, the pistil continues to            grow in length while the anther filaments which hold the            pollen sacs increase in length, the pollen sacs open and the            stigmas separate, each at the tip of a branched style            structure. Toward the end of the flower life, possibly due            to a reduction in turgor pressure, the pistil may shrink in            length and the petals may slightly decrease in area.            Usually, the senescing petals of the flower fold toward the            pistil to some degree, in some cases, completely enfolding            it. Furthermore, the present variety DUP-SWPK is capable of            producing a range of flower forms, from semidouble, to full            double. Because the “doubling” is usually due to the            conversion of sexual flower segments, such as anther tissue,            and less commonly, pistil and stigma tissue, to petal            tissue, the degree of doubling has an effect on the number            of reproductive segments exhibited by such a flower. For            example, a fully double flower can have a greatly reduced            number of anthers with respect to a single flower. Even if            the doubling has not effected the conversion of stigma            tissue into petal tissue, the effect of doubling on the            stigmas is often to deform the staminal column to such an            extent that the stigma are buried in petal or column tissue            and are either under-developed or impossible to locate, and            in some cases, completely absent, with only the pointed            style branches remaining as the flower's attempt to express            female flower segments. Another phenomenon which is observed            in hibiscus flowers which exhibit a high degree of doubling            is the occasional production of multiple pistils, most often            fused at the base or along their lengths. Usually, such            fusion results in pistils which are incomplete, but the            potential for multiple pistils, and thus supernumerary            anthers and stigmas exists with double hibiscus in general,            and the present variety, DUP-SWPK, in particular.-   Disease resistance: DUP-SWPK has not been observed to be resistant    to pathogens common in hibiscus. However, it has been observed in    the green house to have a higher resistance to root rot than that of    many existing hybrid varieties grown on their own roots. If desired,    and if a the risk of virus infection is of no concern, the present    variety can be grafted onto a rootstock and be grown as a grafted    plant.

1. A new and distinct Hibiscus plant named ‘DUP-SWPK’, either grafted oron its own roots, as illustrated and described.